M57 in the constellation, Lyra, is a planetary nebula. Added to Charles Messier’s catalog in January of 1779 who described it as “a dull nebula, but perfectly outlined; as large as Jupiter and looks like a fading planet.” Planetary nebula are not planets, but they are dying stars emitting gases. The particular star that caused this can be seen in the middle of the nebula at 15 magnitude; it is a white dwarf star, and is the remainder of a sunlike star. The central region is dark due to emitting UV light, and the green color is caused by oxygen and nitrogen while the outer red region is hydrogen. The distance is not well known; more about the distance can be read in the link below on the Messier Catalog.
This nebula is very small in the eyepiece, but on a clear night it can be seen shining almost looking like a little cheerio in the sky, or a smoke ring. The starfield around it can sometimes wash out the view, or even a thin layer of clouds can make this a hard target to spot. Given some close bright stars making of the constellation, Lyra, it can be easily located.
This image is 62 light frames at 45 seconds a piece, ISO 800 with 40 darks. The main image was one stack and process, and the larger image in the upper left corner was another stack with a 2x drizzle applied to it, and then cropped and placed in this image for a slightly larger view.
For last years attempt at the ring nebula click through to the post here.
I get all my Deep Sky object information from The Messier Catalog.
Omni XLT 150 with CG-4 mount
Modded Canon 350D
T-ring and adapter
Polar Scope for alignment